How Kim Kardashian’s Curvy Back Broke the Internet
One of the biggest media moments of 2014 was when Kim Kardashian ‘broke the Internet’ with her bottom-baring snapshots. Kim balanced a champagne flute on her denuded derrière, proving that you don’t need a coffee table when your bum is as big as a barn.
This was the most obvious evidence yet that a large female rear end is back in fashion. In the Elizabethan era women wore huge farthingales under tent-sized gowns, and no on-trend Victorian lady would be seen without her corset and butt-boosting bustle. Today, cosmetic surgery and Photoshop serve much the same purpose, nipping and nudging women’s bodies closer to an ever changing ideal.
As someone who researches human attraction for a living, I’m often asked by journalists why we’ve suddenly become so obsessed with women’s bottoms. When I say often, what I really mean is occasionally. And when I say occasionally, I mean once. Anyway, the truth is that we’re probably not that interested in massive trouser mountains. Instead what may be catching our eye is the sinuous curve of a woman’s lower back.
David Lewis and his colleagues at The University of Texas at Austin have published new research on ‘lumbar curvature’ and how it relates to attractiveness.
They drew a series of side-on images of a woman, with her back curvature varying from as straight as the proverbial steel ramrod to as bendy as a rubber horseshoe. Then they showed these images to a group of men and had them pick out the one they thought was most appealing.
The results of the study showed that men preferred an angle of around 45° between a woman’s lower back and her lovely lady lumps.
Why should this 45° angle be the most attractive? Well, Lewis suggests that it’s because a somewhat curvy lower back indicates that a woman has a healthy degree of vertebral wedging. What’s vertebral wedging? It describes the wedge-like shape of women’s third to last vertebra. In women, but not men, this bone is slightly thinner in the back that in the front. And the reason why women need this doorstopper backbone? It’s to help them properly position their weight during pregnancy. If women had spines like flagpoles, as soon as they hit the second trimester they’d topple onto their faces. Vertebral wedging, like wide hips and the ability to spend time in the company of a crying infant without succumbing to the desire to launch it out of the window, is a biological adaptation that makes women better suited for child rearing.
And, just as men find themselves drawn to women with a hourglass figure, whose hips are wide enough to pop a sprog with a head the size of a bowling ball, so too they are attracted to a curvy back, built to counterbalance the load of a womb filled to busting with a miniature squatter.
Follow up research indicated that the effect of lumbar curvature on attractiveness was not a by-product of men’s preference for greater buttock mass. If you’re looking to make the internet grind to a halt, a bendy back might be more important than a bum that looks like two wrestlers fighting in an oily sack. Sorry, Kim!
Lewis, D. M. G., Russell, E. M., Al-Shawaf, L., & Buss, D. M. (in press). Lumbar curvature: A novel evolved standard of attractiveness.Evolution and Human Behavior. Read summary
The content of this post first appeared in the 24 March 2015 episode of The Psychology of Attractiveness Podcast.
